Process uniformity in mainframe processing chambers can be poor due to a variety of factors. Rotating wafers throughout the process can help improve the within wafer uniformity. The amount of rotation small and/or a few rotations can improve the uniformity. Rotating a wafer during processing can be time consuming and uses additional process hardware or space. For example, the wafers can be moved to a dedicated region of a processing tool where the wafer can be rotated. This is inefficient from a throughput perspective and uses additional floor space for a batch processing tool or cluster tool.
Therefore, there is a need in the art for methods and apparatus to rotate wafers during processing in mainframe process chambers to increase within wafer uniformity.